Self-wetting adhesive composition

ABSTRACT

According to various embodiments of the present disclosure, a composition includes about 5 to about 40 parts by weight of a solute copolymer component. The solute component optionally has one Tg or Tm of at least 25° C. The composition further includes about 60 to about 95 parts by weight of a solvent monomer. The solvent monomer component includes (meth)acrylate monomers and a multifunctional acrylate. The sum of the solute copolymer component and the solvent monomer component is 100 parts by weight. The composition further includes about 5 to about 100 parts of a plasticizer, relative to the 100 parts.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a national stage filing under 35 U.S.C. 371 ofPCT/2018/018626, filed Feb. 19, 2018, which claims the benefit ofprovisional Application No. 62/461,147, filed Feb. 20, 2017, thedisclosure of which is incorporated by reference in its/their entiretyherein.

BACKGROUND

Pressure-sensitive tapes may be used in the home and workplace. Forexample, the tapes can be used to attach an object to a substrate suchas a smooth glass surface. Properties of the tape such as the wet outrate of the tape and the peel strength of the tape can directly affectthe ability of the tapes to attach the object to the substrate.

SUMMARY

According to various embodiments of the present disclosure, acomposition includes about 5 to about 40 parts by weight of a solutecopolymer component. The solute component optionally has one T_(g) orT_(m) of at least 25° C. And in some embodiments, the solute componenthas one T_(g) or T_(m) of at least 25° C. The composition furtherincludes about 60 to about 95 parts by weight of a solvent monomer. Thesolvent monomer component includes (meth)acrylate monomers and amultifunctional acrylate. In some embodiments, sum of the solutecopolymer component and the solvent monomer component is 100 parts byweight. The composition further includes about 5 to about 100 parts of aplasticizer, relative to the 100 parts of solvent monomer and solutecopolymer.

Further embodiments are directed to a method of making a cured adhesivefilm including at least partially polymerizing a composition includingabout 60 to about 95 parts by weight of a solvent monomer componentcomprising (meth)acrylate monomers and a multifunctional acrylate. Thecomposition further includes about 5 to about 40 parts by weight of asolute copolymer component optionally having one T_(g) or T_(m) of atleast 25° C. to give an at least partially polymerized composition. Thesum of the solute copolymer component and the solvent monomer componentis 100 parts by weight. According to various embodiments, the partiallypolymerized composition can be cured to form an adhesive film.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1-3 are photographs of scratch testing, according to variousembodiments of this disclosure.

DETAILED DESCRIPTION

The present disclosure provides novel compositions that can be cured toform an adhesive film. According to various embodiments, the adhesivefilm is substantially self-wetting when it is applied to a substantiallysmooth surface. That is, the adhesive film undergoes a substantiallyspontaneous wet-out with substantially no need to apply externalpressure.

The composition can be cured directly or a portion of the compositioncan be prepolymerized to form a syrup and subsequently cured. Asdescribed further herein, the adhesive film cast from the compositionsof the present disclosure can have several beneficial features comparedto other films that have a high-wet out rate. For example, the adhesivefilm can have good peelability and demonstrate good shear hold. Forexample the adhesive films can remain bonded to an adherend for anamount of time ranging from 20,000 minutes to about 30,000 minutes whena force ranging from about 13.79 kPa (2 lb/in²) to about 62.05 kPa (9lb/in²) is applied. The high shear holding power of these adhesive filmscan make them suitable for use as mounting objects on smooth surfacessuch as glass, tile, or stainless steel. Many different objects can bemounted using the adhesive films. For example, decorative objects suchas pictures, posters, calendars, clocks, attachment hooks can be mountedon smooth surfaces by these adhesive films. The adhesive films can alsoshow good scratch-resistance properties.

The adhesive films of this disclosure provide the desired balance oftack, peel adhesion, and shear holding power, and further conform to theDahlquist criteria; e.g., the modulus of the adhesive at the applicationtemperature (e.g., at room temperature), is less, for example, than3×10⁶ dynes/cm² at a frequency of 1 Hz.

The adhesive films can be formed from a composition that includes asolute copolymer component, a solvent monomer component, and aplasticizer component. The solute copolymer component optionally has oneT_(g) or T_(m) of at least 25° C. In various embodiments of thecomposition the T_(g) is at least 25° C. In various embodiments of thecomposition the T_(m) is at least 25° C. The solvent monomer componentcomprises (meth)acrylate monomers and a multifunctional acrylate. Thesolute copolymer can range from about 5 to about 40 parts by weightrelative to the solvent monomer, or from about 10 to about 20 parts byweight relative to the solvent monomer, or from about 10 to about 15parts by weight relative to the solvent monomer, or from about 15 toabout 20 parts by weight relative to the solvent monomer. The solventmonomer can range from about 20 to about 95 parts by weight relative tothe solute copolymer, or about 20 to about 60 parts by weight relativeto the solute copolymer, or from about 30 to about 50 parts by weightrelative to the solute copolymer, or from about 50 to about 90 parts byweight relative to the solute copolymer or from about 60 to about 95parts by weight relative to the solute copolymer. The sum of the partsof the solute copolymer and the solvent monomer equals 100 parts byweight.

The plasticizer can range from about 5 to about 100 parts, or about 10to about 80 parts, about 15 to about 40 parts, about 30 to about 40parts, or about 40 to about 70 parts relative to the solute copolymerand the solvent monomer.

The solute copolymer can be selected from a polyurethane, a polyester, apolyvinylpyrrolidone, a poly(methyl methacrylate), a poly((meth)acrylate), a poly(butyl acrylate), a polymer derived from a polyvinylalcohol and an alkanal, a polyacrylonitrile, a polyolefin, a polyurea, apolybutadiene, a polystyrene, any copolymer thereof, and any combinationthereof. The alkanal can have the structure according to formula I:

In Formula (I), R¹ can be selected from (C₁-C₂₀)hydrocarbyl. Inadditional embodiments R¹ can be (C₁-C₂₀)alkyl. In additionalembodiments, the solute copolymer component comprises a poly(vinylbutyral).

In further embodiments, the solute copolymer comprises a block copolymerof poly(methyl methacrylate) and poly(n-butyl acrylate).

The solvent monomer component can be about 5 to about 95 parts by weightof low T_(g) monomers or about 60 to about 95 parts by weight of the lowT_(g) monomers, or about or about 10 to about 50, or about 20 to about40, or about 60 to about 90 parts by weight of the low T_(g) monomers.The solvent monomer component can also include an acid functionalmonomer. The acid functional monomer can be about 0 to about 20 parts byweight of the solvent monomer, or about 0 to about 15 parts by weight ofthe solvent monomer, or about 0 to about 10 parts by weight of thesolvent monomer. The solvent monomer can also include a non-acidfunctional polar monomer. The non-acid functional polar monomer can beabout 0 to about 20 parts of the solvent monomer or about 0 to about 15parts by weight of the solvent monomer, or about 0 to about 10 parts byweight of the solvent monomer. The solvent monomer can also include amultifunctional acrylate cross-linking agent. The multifunctionalacrylate cross-linking agent can be about 5 to about 50 parts of thesolvent monomer or about 10 to about 30 parts of the solvent monomer orabout 15 to about 25 parts by weight of the solvent monomer. In total,the sum of the low T_(g) monomers, the acid functional monomers, thenon-acid functional polar monomer, and the multifunctional acrylatecross-linking agent equals 100 parts by weight of the solvent monomer.

The (meth)acrylate monomer of the solvent monomer can be a monomeric(meth)acrylic ester of a non-tertiary alcohol, which includes from 1 to18 carbon atoms or from 4 to 12 carbon atoms. A mixture of such monomersmay be used.

Examples of monomers suitable for use as the (meth)acrylate monomerinclude the esters of either acrylic acid or methacrylic acid withnon-tertiary alcohols such as ethanol, 1-propanol, 2-propanol,1-butanol, 2-butanol, 1-pentanol, 2-pentanol, 3-pentanol,2-methyl-1-butanol, 3-methyl-1-butanol, 1-hexanol, 2-hexanol,2-methyl-1-pentanol, 3-methyl-1-pentanol, 2-ethyl-1-butanol,3,5,5-trimethyl-1-hexanol, 3-heptanol, 1-octanol, 2-octanol,isooctylalcohol, 2-ethyl-1-hexanol, 1-decanol, 2-propylheptanol,1-dodecanol, 1-tridecanol, 1-tetradecanol, citronellol,dihydrocitronellol, and the like. In some embodiments, the(meth)acrylate monomer is the ester of (meth)acrylic acid with butylalcohol or isooctyl alcohol, or a combination thereof, althoughcombinations of two or more different (meth)acrylate ester monomers aresuitable as well.

In some embodiments, the (meth)acrylate monomer is the ester of(meth)acrylic acid with an alcohol derived from a renewable source, suchas 2-octanol, citronellol, dihydrocitronellol. In some embodiments aportion of the above described (meth)acrylate esters may be substitutedwith (meth)acrylates derived from 2-alkyl alkanols.

In examples where the solvent monomer component includes the acidfunctional monomer, the acid functional group of the monomer may be anacid per se, such as a carboxylic acid or an ester thereof, or a portionmay be salt thereof, such as an alkali metal carboxylate. Useful acidfunctional monomers include, but are not limited to, those selected fromethylenically unsaturated carboxylic acids, ethylenically unsaturatedsulfonic acids, ethylenically unsaturated phosphonic acids, and mixturesthereof. Exemplary examples ethylenically unsaturated carboxylic acidsmay include those selected from acrylic acid, methacrylic acid, itaconicacid, fumaric acid, crotonic acid, citraconic acid, maleic acid, oleicacid, (3-carboxyethyl (meth)acrylate, 2-sulfoethyl methacrylate, styrenesulfonic acid, and mixtures thereof. Examples of ethylenicallyunsaturated sulfonic acids may include vinylsulfonic acid,2-acrylamido-2-methylpropanesulfonic acid, 2-acryloyloxyethanesulfonicacid and 2-methacryloyloxyethanesulfonic acid, 2-acryloyloxy- and3-methacryloyloxypropanesulfonic acid, vinylbenzenesulfonic acid, andmixtures thereof. Examples of ethylenically unsaturated phosphoric acidsmay include vinylphosphonic acid vinyl phosphoric acid, and mixturesthereof.

In addition to the low T_(g) monomer and optional acid functionalmonomer, a copolymer made using those two components may optionallyinclude other monomers, such as non-acid functional polar monomers asstated above, vinyl monomers and vinyl ether monomers, provided theresultant copolymer has a T_(g) of <0° C., maintains compatibility withthe plasticizer, and has the requisite optical and adhesive properties.Representative examples of suitable non-acid functional polar monomersinclude but are not limited to a hydroxyl containing monomer, anethylenically unsaturated amine containing monomer, or a combinationthereof. Additionally, the non-acid functional polar monomer may include2-hydroxyethyl (meth)acrylate; N-vinylpyrrolidone; N-vinylcaprolactam;acrylamide; mono- or di-N-alkyl substituted acrylamide; t-butylacrylamide; dimethylaminoethyl acrylamide; N-octyl acrylamide;poly(alkoxyalkyl) (meth)acrylates including 2-(2-ethoxyethoxy)ethyl(meth)acrylate, 2-ethoxyethyl (meth)acrylate, 2-methoxyethoxyethyl(meth)acrylate, 2-methoxyethyl methacrylate, polyethylene glycolmono(meth)acrylates; alkyl vinyl ethers, including vinyl methyl ether;and mixtures thereof. Suitable examples of polar monomers include thoseselected from the group of polyethylene glycol mono(meth)acrylates,2-hydroxyethyl (meth)acrylate and N-vinylpyrrolidinone.

A useful predictor of the T_(g) for specific combinations of variousmonomers can be computed by application of the Fox Equation:1/T_(g)=ΣWi/T_(g,i). In this equation, T_(g) is the glass transitiontemperature of the mixture, Wi is the weight fraction of component i inthe mixture, and T_(g,i) is the glass transition temperature ofcomponent i, and all glass transition temperatures are calculated inKelvin (K). As used herein the term “low T_(g) monomer” refers to amonomer, which when homopolymerized, produces a (meth)acrylate copolymerhaving a T_(g) ranging from about −50° C. to about 0° C., or about −20°C. to about −50° C. as calculated using the Fox Equation. Alternatively,the glass transition temperature can be measured in a variety of knownways, e.g., through differential scanning calorimetry (DSC).

In order to provide sufficient cohesive strength of the adhesivecomposition, a multifunctional (meth)acrylate is incorporated into theblend of polymerizable monomers. Examples of useful multifunctional(meth)acrylate include, but are not limited to, di(meth)acrylates,tri(meth)acrylates, and tetra(meth)acrylates, such as 1,6-hexanedioldi(meth)acrylate, poly(ethylene glycol) di(meth)acrylates, polybutadienedi(meth)acrylate, polyurethane di(meth)acrylates, and propoxylatedglycerin tri(meth)acrylate, and mixtures thereof. The amount andidentity of multifunctional (meth)acrylate can tailored depending uponapplication of the adhesive composition, as further exemplified below.

The composition further comprises a plasticizer that acts to increaseflexibility of the cured adhesive film by internal modification (e.g.,solvation) of the adhesive film and enhances the wet out properties ofthe adhesive film. The plasticizer may be solid or liquid at roomtemperature. If solid, the plasticizer can be softened or liquefied byheating to cause the plasticizer to melt.

If solid, the plasticizer can be a crystalline solid, displaying ameasurable melting temperature when measured using Differential Scanningcalorimetry (DSC). The melting temperature of solid plasticizers used inthe present disclosure may be relatively low (e.g., about 10° C. toabout 60° C.) so as to minimize any heating that may be required. Whenplasticizers are used that are liquid at room temperature, heating isnot required to cause the bond to form in a timely manner.

Some migration of the plasticizer from or throughout the adhesive filmcan be tolerated, such as minor separation due to compositionequilibrium or temperature influences, but the plasticizer does notmigrate to the extent of phase separation between the cured adhesivecopolymer and plasticizer.

The plasticizer is, in some embodiments, non-volatile. “Non-volatile”refers to plasticizers that do not substantially vaporize under bondformation conditions. That is, the plasticizers generate less than 3%VOC (volatile organic content). The VOC content can be determinedanalogously to ASTM D 5403-93 by exposing the plasticizer compoundedadhesive to 100° C. in a forced draft oven for one hour. If less than 3%of the plasticizer is lost from the compounded adhesive, then theplasticizer is considered “non-volatile.”

The plasticizer is, in some embodiments, non-reactive with othercomponents of the adhesive or air. For example, the plasticizer may beinert with respect to other components in the system, including theadhesive (co)polymer and substrate. When the plasticizer is non-reactivewith respect to air, loss of optical properties, such as by hazing oryellowing, may be minimized.

Useful plasticizers have a broad range of molecular weights andarchitectures. The plasticizers may be polymeric or monomeric. Classesof suitable plasticizers include those selected from esters, ethers,hydrocarbons, paraffins, sulphonamides, sulfonates, terephthalates,terpenes, and trimellitates. Common among ester-based plasticizers areesters of mono- or di-basic acids such as myristate esters, phthalateesters, adipate esters, phosphate esters, citrates, trimellitates,glutarates, and sebacate esters (e.g., dialkyl phthalates, such asdibutyl phthalate, diisoctyl phthalate, dibutyl adipate, dioctyladipate; 2-ethylhexyl diphenyl diphosphate; t-butylphenyl diphenylphosphate; butyl benzylphthalates; dibutoxyethoxyethyl adipate;dibutoxypropoxypropyl adipate; acetyltri-n-butyl citrate;dibutylsebacate; etc.). Phosphate ester plasticizers are commerciallysold under the trade designation SANTICIZER from Monsanto; St. Louis,Mo. Glutarate plasticizers are commercially sold under the tradedesignation PLASTHALL 7050 from CP. Hall Co.; Chicago, Ill.

Additional examples of ester-based plasticizers include aliphaticmonoalkyl esters, aromatic monoalkyl esters, aliphatic polyalkyl esters,aromatic polyalkyl esters, polyalkyl esters of aliphatic alcohols,phosphonic polyalkyl esters, aliphatic poly(alkoxylated) esters,aromatic poly(alkoxylated) esters, poly(alkoxylated) ethers of aliphaticalcohols, and poly(alkoxylated) ethers of phenols. In some embodimentsthe esters are derived from an alcohol or from a renewable source, suchas 2-octanol, citronellol, dihydrocitronellol or from 2-alkyl alkanols.

The compositions described herein can be cured to form the adhesivefilm. To cure the composition it may be necessary to add additionalcomponents to the composition. For example photoinitiators may be addedto aide in polymerization. Additional components such as fillers,antioxidants, stabilizers, and colorants may also be added to thecomposition.

Curing the composition may include treatment with UV radiation, in thepresence of a photoinitiator, which will simultaneously polymerize thesolvent monomers and crosslink the composition with the multifunctionalacrylate.

Any suitable free radical initiator may be used to generate the initialpolymerization in the composition. Examples of suitable thermalinitiators include peroxides such as benzoyl peroxide, dibenzoylperoxide, dilauryl peroxide, cyclohexane peroxide, methyl ethyl ketoneperoxide, hydroperoxides, e.g., tert-butyl hydroperoxide and cumenehydroperoxide, dicyclohexyl peroxydicarbonate,2,2,-azo-bis(isobutyronitrile), and t-butyl perbenzoate. Examples ofcommercially available thermal initiators include initiators availablefrom DuPont Specialty Chemical (Wilmington, Del.) under the VAZO tradedesignation including VAZO™ 67 (2,2′-azo-bis(2-methybutyronitrile))VAZO™ 64 (2,2′-azo-bis(isobutyronitrile)) and VAZO™ 52(2,2′-azo-bis(2,2-dimethyvaleronitrile)), and LUCIDOL™ 70 from ElfAtochem North America, Philadelphia, Pa.

The solute (co)polymer(s) may be prepared conventionally in anon-monomeric solvent and advanced to high conversion (degree ofpolymerization, e.g., 90% to 100%). When solvent (monomeric ornon-monomeric) is used, the solvent may be removed (for example byvacuum distillation) either before or after polymerization.

As described above, curing the composition can include photoinitiatedfree radical polymerization. Advantages of the photopolymerizationmethod are that 1) heating the monomer solution is unnecessary and 2)photoinitiation is stopped completely when the activating light sourceis turned off. Polymerization to achieve a coatable viscosity may beconducted such that the conversion of monomers to polymer ranges fromabout 5% to about 30%, or about 10% to about 20%. Polymerization can beterminated by removing the light source and by bubbling air (oxygen)into the solution to quench propagating free radicals.

During curing the monomer mixture is generally partially polymerized(converted) to produce the copolymer comprising about 5 to about 40parts, or about 10 to about 30 parts, or about 30 parts to about 40parts by weight of the solute copolymer in solvent monomers and has aviscosity of from 50 cP about 1,000 cP when liquefied, or from about 100cP to about 500 cP or from about 500 cP to about 1,000 cP at 22° C.After partial conversion, the multifunctional acrylate, the plasticizerand optional additional monomers are added and the composition isfurther polymerized, by, e.g., photopolymerization using aphotoinitiator.

Useful photoinitiators include benzoin ethers such as benzoin methylether and benzoin isopropyl ether; substituted acetophenones such as 2,2-dimethoxyacetophenone, available as Irgacure™ 651 photoinitiator (CibaSpecialty Chemicals), or as Esacure™ KB-1 photoinitiator (Sartomer Co.;West Chester, Pa.), and dimethoxyhydroxyacetophenone; substitutedα-ketols such as 2-methyl-2-hydroxy propiophenone; aromatic sulfonylchlorides such as 2-naphthalene-sulfonyl chloride; and photoactiveoximes such as 1-phenyl-1,2-propanedione-2-(O-ethoxy-carbonyl)oxime.

Other useful photoinitiators include photoactive compounds such asketones having a basis cis-4-tert-butyl-1-benzoylcyclohexane or2-benxoyladamantane structure that undergo a Norrish I cleavage togenerate free radicals that can initiate by addition to the acrylicdouble bonds. Additional photoinitiator can be added to the mixture tobe coated after the copolymer has been formed, e.g., photoinitiator canbe added to the composition.

The composition and the photoinitiator may be irradiated with UVradiation to polymerize the monomer component(s). UV light sources canbe of two types: 1) relatively low light intensity sources such asbacklights which provide generally 10 mW/cm² or less (as measured inaccordance with procedures approved by the United States NationalInstitute of Standards and Technology as, for example, with a Uvimap™ UM365 L-S radiometer manufactured by Electronic Instrumentation &Technology, Inc., in Sterling, Va.) over a wavelength range of 280 to400 nanometers and 2) relatively high light intensity sources such asmedium pressure mercury lamps which provide intensities generallygreater than 10 mW/cm², for example between 15 and 450 mW/cm². Whereactinic radiation is used to fully or partially polymerize thecomposition, high intensities and short exposure times may be employed.For example, an intensity of 600 mW/cm² and an exposure time of about 1second may be used successfully. Intensities can range from about 0.1 toabout 150 mW/cm², or from about 0.5 to about 100 mW/cm², or from about0.5 to about 50 mW/cm². Such photoinitiators may be present in an amountof from about 0.1 to about 1.0 pbw per 100 pbw, or from about 0.3 toabout 0.7 pbw per 100 pbw of the polymer composition.

It will be understood that curing can produce a “dead polymer” in theinitial free radical polymerization; e.g., a fully polymerized, notfree-radically polymerizable polymer. Subsequently the solvent monomersdo not free-radically polymerize onto the extant solute copolymer. Uponcompounding the polymer, further exposure to UV initiates free radicalpolymerization of the solvent monomers and multifunctional acrylatecrosslinking agent to produce a distinct crosslinked copolymer. Uponcuring, the product may be characterized as a homogenous mixture of a) alow T_(g) (co)polymer (from the initial polymerization, b) a highlycrosslinked low T_(g) (co)polymer (from the subsequent polymerization ofthe monomer and multifunctional acrylate component and c) theplasticizer.

If desired, the composition may be coated on a substrate prior tofurther polymerization.

Additionally, other additives such as fillers, antioxidants,stabilizers, and colorants may be blended with the adhesive forbeneficial properties. In some embodiments the composition may includeone or more fillers. In many embodiments the filler is of a type andused in amounts such that incorporation does not deleteriously affectthe optical and adhesive properties of the adhesive. In someembodiments, small amounts of filler may be used to improve the cohesivestrength of the adhesive.

Such compositions may include 1 wt %, to about 50 wt % or about 10 wt %to about 40 wt % filler, based on the total weight of the composition.

Fillers may be selected from one or more of a wide variety of materials,as known in the art, and include organic and inorganic filler. Inorganicfiller particles include silica, submicron silica, zirconia, submicronzirconia, non-vitreous microparticles, nanosized silica particles,nanosized metal oxide particles, and combinations thereof.

In some embodiments, the composition comprises a nanoparticle fillerhaving an average primary particle size ranging from about 5 nanometersto about 100 nanometers or from about 10 nanometers to about 50nanometers. As used herein, the term “primary particle size” refers tothe size of a non-associated single particle.

In some embodiments, surface modified filler can be used. The surfacemodifying agents for the fillers may enhance dispersibility orrheological properties. Examples of surface modifying agents includesilanes such as aryl polyethers, alkyl, hydroxy alkyl, hydroxy aryl, oracrylate, amino alkyl functional silanes.

In some embodiments the filler is hydrophobic fumed silica, such asAerosil™ R972 fumed silica from Degussa.

According to some embodiments, the adhesive film can be prepared by asyrup polymerization technique that include prepolymerizing part of thecomposition. As used herein “syrup polymer composition” refers to asolution of a solute (co)polymer in one or more solvent monomers, thecomposition can have a viscosity of from 50 cP about 1,000 cP whenliquefied, or from about 100 cP to about 500 cP or from about 500 cP toabout 1,000 cP at 22° C. Here, a monomer mixture comprising the (meth)acrylate monomer, the optional acid functional monomer and othermonomers are combined and partially polymerized using a thermal- orphotoinitiator. The resulting syrup polymer, comprising a solute(meth)acrylate copolymer and unreacted solvent monomers, is thencombined with the multifunctional acrylate crosslinking agent andphotoinitiator. If desired, additional solvent monomers and initiatorsmay be added after the initial partial polymerization. The additionalmonomers charged may be the same or different than the initial monomercharge.

The cured compositions form adhesive films that have several usefulfeatures. Examples of such features are described below.

The adhesive films cast from compositions of the present disclosureexhibits great conformability permitting them to spontaneously wet outon substrates such as glass or any other hard and smooth surface. Thusthe adhesive films may be referred to as self-wetting. By “self-wetting”it is meant that the adhesive film exhibits spontaneous wetting out on asmooth surface to which it is applied with little or no externalpressure. In some embodiments a wet-out rate of the adhesive film rangesfrom about 7.7 s/dm² (0.5 s/in²) to about 775.0 s/dm² (50 s/in²), orfrom about 418.5 s/dm² (27 s/in²) to about 620.0 s/dm² (40 s/in²), orfrom about 7.7 s/dm² (0.5 s/in²) to about 155.0 s/dm² (10 s/in²).

The surface characteristics of the films also permit the adhesive filmto be bonded and removed from the substrate repeatedly for repositioningor reworking. The strong cohesive strength of the adhesive film givesthem structural integrity limiting cold flow and giving elevatedtemperature resistance in addition to permanent removability. In someembodiments the initial removability of the adhesive film bonded to aglass substrate, as measured by the 180° Peel Adhesion test ranges fromabout 0.5 Newtons/decimeter to about 5 Newtons/decimeter.

In various embodiments an adhesive film cast from compositions of thepresent disclosure is scratch resistant when subjected to a linearstroke of a stylus of having a speed ranging from about 0.16 cm/s toabout 0.5 cm/s and where a weight applied to the stylus ranging fromabout 0 grams to about 1500 grams. Without intending to be bound to anyspecific theories, the inventors believe that the solute copolymerincreases the scratch resistance of the adhesive film. Therefore, theadhesive film is more scratch resistant than a corresponding adhesivefilm that is substantially free of the solute copolymer component.

In addition, a 1.27 cm (0.5 inch) wide by 1.27 cm (0.5 inch) long sampleof the adhesive film remains adhered to a substrate for a time rangingfrom approximately 10 minutes to 40 days when a force ranging from about13.79 kPa (2 lbs/in²) to about 10 lbs/in² is applied to the adhesivefilm. Without intending to be bound to any theories the inventorsbelieve that the solute copolymer increases adherence of the adhesivefilm. Therefore adhesive film that include the solute copolymer remainadhered to the substrate for a substantially longer period of time thana corresponding adhesive film that is substantially free of the solutecopolymer component.

The adhesive films formed from the cured compositions can have manydifferent applications. For example, adhesive articles may include theadhesive film and be prepared by forming the adhesive film on a suitablesupport, such as a flexible backing. The adhesive film can be formed bycoating the support with the composition and curing the compositionthereon. Examples of materials that can be included in the flexiblebacking include polyolefins such as polyethylene, polypropylene(including isotactic polypropylene), polystyrene, polyester, polyvinylalcohol, poly(ethylene terephthalate), poly(butylene terephthalate),poly(caprolactam), poly(vinylidene fluoride), polylactides, celluloseacetate, and ethyl cellulose and the like. Commercially availablebacking materials useful in the invention include kraft paper (availablefrom Monadnock Paper, Inc.); cellophane (available from Flexel Corp.);and porous films obtained from poly(ethylene) and poly(propylene), suchas Teslin™ (available from PPG Industries, Inc.), and Cellguard™(available from Hoechst-Celanese).

The adhesive film may also be formed on microstructured surfaces.Microstructured surfaces can be made in various ways, including, e.g.,using micro-replication techniques, laser ablation or embossing. In someembodiments of this disclosure, a microstructured resin layer isprovided on a polymeric film substrate such as a polyethyleneterephthalate (PET) or polycarbonate film. A microreplication tool canbe fabricated using diamond turning methods such as those described, forexample, in PCT Published Application No. WO 00/48037 (Campbell et al.),and U.S. Pat. No. 7,350,442 (Ehnes et al.) and U.S. Pat. No. 7,328,638(Gardiner et al.). The tool can be used in a cast-and-cure process asdescribed, for example, in U.S. Pat. No. 5,175,030 (Lu et al.) and U.S.Pat. No. 5,183,597 (Lu), to produce microstructures such as sinusoidalstructures on a substrate film. In some embodiments, an acrylate resinis used to form the structures.

The backing may also be formed of metal, metalized polymer films, orceramic sheet materials. The adhesive articles herein may take the formof any article conventionally known to be utilized with pressuresensitive adhesive compositions such as labels, tapes, signs, covers,marking indicia, and the like.

The above-described adhesive films can be formed, in part, on asubstrate by depositing the composition thereon using conventionalcoating techniques, which can be modified as appropriate to theparticular substrate. For example, the composition can be applied to avariety of solid substrates by methods such as roller coating, flowcoating, dip coating, spin coating, spray coating, knife coating, anddie coating. These various methods of coating allow the compositions tobe placed on the substrate at variable thicknesses thus allowing a widerrange of use of the compositions. Coating thicknesses may vary, butcoating thicknesses of 2-500 microns (dry thickness), or in someembodiments about 10 to 250 microns, are contemplated.

In some embodiments, the composition, e.g., the solute (co)polymer,unreacted monomers, multifunctional acrylate crosslinking agent andplasticizer is coated on a backing or release liner, and then furtherpolymerized.

The substrate is selected depending on the particular application inwhich it is to be used. For example, the adhesive can be applied tosheeting products, (e.g., decorative graphics and reflective products),label stock, and tape backings. Additionally, the adhesive may beapplied directly onto a substrate such as an automotive panel, a glasswindow, a computer screen or the screen of a hand-held device or onto asubstrate such as an automotive panel, a glass window, a computer screenor the screen of a hand-held device, or other smooth surfaces such as akitchen or bathroom surface; so that another substrate or object can beattached to substrate.

The adhesive film can also be provided in the form of an adhesivetransfer tape in which at least one layer of the adhesive film isdisposed on a release liner for application to a permanent substrate ata later time. The adhesive film can also be provided as a single coatedor double coated tape in which the adhesive is disposed on one or bothopposing sides of a permanent backing.

Examples of adhesive articles in which the self-wetting and removabilityfeatures of the adhesive film that may be important include, forexample: large format articles such as graphic articles and protectivefilms; and information display devices.

Large-format graphic articles or protective films typically include athin polymeric film backed by an adhesive. These articles may bedifficult to handle and apply onto a surface of a substrate. The largeformat article may be applied onto the surface of a substrate by what issometimes called a “wet” application process. The wet applicationprocess involves spraying a liquid, typically a water/surfactantsolution, onto the adhesive side of the large format article, andoptionally onto the substrate surface. The liquid temporarily“detackifies” the adhesive so the installer may handle, slide, andre-position the large format article into a desired position on thesubstrate surface. The liquid also allows the installer to pull thelarge format article apart if it sticks to itself or prematurely adheresto the surface of the substrate. Applying a liquid to the adhesive mayalso improve the appearance of the installed large format article byproviding a smooth, bubble free appearance with good adhesion build onthe surface of the substrate. Examples of a large format protectivefilms include window films such as solar control films, shatterprotection films, decoration films and the like. In some instances theadhesive film may be a multilayer adhesive film such as a multilayer IRfilm (e.g., an infrared reflecting film), such as a microlayer filmhaving selective transmissivity such as an optically clear but infraredreflecting film.

While the wet application process has been used successfully in manyinstances, it can be a time consuming and difficult process. In otherapplications, such as information display devices, the wet applicationprocess cannot be used, but the adhesive films can be used. The adhesivefilms can advantageously be applied through a dry installation process.A “dry” application process is generally desirable for installing largeformat graphic articles.

Examples of information display devices include devices with a widerange of display area configurations including liquid crystal displays,plasma displays, organic light emitting diode (OLED) displays, front andrear projection displays, cathode ray tubes and signage. Such displayarea configurations can be employed in a variety of portable andnon-portable information display devices including personal digitalassistants, cell phones, touch-sensitive screens, wrist watches, carnavigation systems, global positioning systems, depth finders,calculators, electronic books, CD or DVD players, projection televisionscreens, computer monitors, notebook computer displays, instrumentgauges, instrument panel covers, signage such as graphic displays(including indoor and outdoor graphics, bumper stickers, etc.)reflective sheeting, virtual reality (VR) devices, augmented reality(AR) devices and the like. Thus using the adhesive film, articles can bemore easily attached to a large substrate because they are self-wettingand yet they may be easily removed and repositioned as needed.

A wide variety of information display devices are in use, bothilluminated devices and non-illuminated devices. Many of these devicesutilize adhesive articles, such as adhesive coated films, as part oftheir construction. One adhesive article frequently used in informationdisplay devices is a protective film. Such adhesive films are frequentlyused on information display devices that are frequently handled or haveexposed viewing surfaces.

In some embodiments, the adhesive films of this disclosure may be usedto attach such films to information display devices or incorporated intoinformation display devices because the adhesive films have theproperties of optical clarity (e.g., less than about 5% haze or lessthan about 2% haze), self-wetting and removability. The adhesiveproperty of optical clarity permits the information to be viewed throughthe adhesive film without interference. The features of self-wetting andremovability permit the adhesive film to be easily applied to the frontsurface of a display, removed and reworked if needed during assembly andalso removed and replaced during the working life of the informationdisplay device. The adhesive films of the disclosure can also be used toposition optical films between a display panel and the outer glass layerof the display or within display devices. For example an optical film(e.g., a multilayer optical film or a microstructured optical film) canbe provided with a layer of the cured adhesive composition on a releaseliner. The release liner can then be removed and the optical film can beapplied to the appropriate surface in the display device such as, e.g.,on a glass or hard coat surface, emission layer, circular polarizer,linear polarizer or encapsulation layer (e.g., glass or thin filmencapsulation layer for OLED) or the like. In various embodiments ofthis disclosure, it has been discovered that adhesion builds over timewhen the adhesive films are used on polar surfaces such as polarizers.

In some embodiments, the adhesive films of this disclosure may be usedwith VR device or AR systems. For example, an adhesive articlecomprising a protective film (e.g., glass or PET), optically clearadhesive, optical film and the cured adhesive composition and a releaseliner may be provided. The release liner can then be removed and thearticle can be applied to the appropriate surface (e.g., the lenses) ofa VR or AR head set. A display can then be brought into opticalproximity to optical film. The adhesive film of the disclosure may havea thickness greater than about 0.03 millimeters, generally an averagebirefringence (absolute) of less than 1×10′, average light transmissionranging from about 85% to about 100%, or from about 90% to about 95% anda CIELAB b* ranging from about 0.5 units to about 1.5 units, or about0.5 units to about 1.0 unit for samples with adhesive thickness of about500 microns. Further, the adhesive layer of these articles may haveoptical properties at least equal to those of the composite article sothe articles appear transparent.

In some embodiments this disclosure provides solar control articles,e.g., films including the adhesive film that may be applied to windowsto selectively reduce the transmissivity over the spectral region ofinterest including UV, visible and IR. The solar control articlescomprise a solar control film and a layer of an adhesive of thisdisclosure on a major surface thereof. Some known solar control filmsdesirably have transmissivity on at least 80% in the visible range(400-700 nm), and reduced transmissivity of less than 80%, less than70%, or less than 60% in the IR (700-2000 nm) and/or UV (100 to 400 nm)ranges. Solar control films include dyed or pigmented and vacuum-coatedpolymeric films that reduce the transmissivity of various spectralregions from the incident light, e.g., sunlight. To reduce heat loadfrom incident light, solar transmission is blocked in either the visibleor the infrared portions of the solar spectrum (e.g., at wavelengthsranging from 400 nm to 2500 nm or greater.) Primarily throughabsorption, dyed films can control the transmission of visible light andconsequently provides glare reduction. However, dyed films generally donot block near-infrared solar energy and consequently are not completelyeffective as other solar control films. Other window films arefabricated using vacuum-deposited grey metals, such as stainless steel,inconel, monel, chrome, or nichrome alloys. The deposited grey metalfilms offer about the same degrees of transmission in the visible andinfrared portions of the solar spectrum. The grey metal films arerelatively stable when exposed to light, oxygen, and/or moisture, and inthose cases in which the transmission of the coatings increases due tooxidation, color changes are generally not detectable. After applicationto clear glass, grey metals block light transmission by approximatelyequal amounts of solar reflection and absorption. Vacuum-depositedlayers such as silver, aluminum, and copper control solar radiationprimarily by reflection and are useful only in a limited number ofapplications due to the high level of visible reflectance. A modestdegree of selectivity (e.g., higher visible transmission than infraredtransmission) is afforded by certain reflective materials, such ascopper and silver. The metal deposited films may also have air- andwater-vapor barrier properties. Additionally, solar control films basedon multilayer optical films (MLOF) have been developed which, in someembodiments, comprise hundreds or even thousands of film layers andoptional nanoparticles, and which selectively transmit or reflect basedon small differences in the refractive indices of adjacent film layersand reflectance or absorbance of the nanoparticles. The film layers havedifferent refractive index characteristics so that some light isreflected at interfaces between adjacent layers. The layers aresufficiently thin so that light reflected at a plurality of theinterfaces undergoes constructive or destructive interference in orderto give the film the desired reflective or transmissive properties. Foroptical films designed to reflect light at ultraviolet, visible, ornear-infrared wavelengths, each layer generally has an optical thickness(e.g., a physical thickness multiplied by refractive index) of less thanabout 1 micrometer. Thicker layers can, however, also be included, suchas skin layers at the outer surfaces of the film, or protective boundarylayers disposed within the film that separate packets of layers.

Throughout this document, values expressed in a range format should beinterpreted in a flexible manner to include not only the numericalvalues explicitly recited as the limits of the range, but also toinclude all the individual numerical values or sub-ranges encompassedwithin that range as if each numerical value and sub-range is explicitlyrecited. For example, a range of “about 0.1% to about 5%” or “about 0.1%to 5%” should be interpreted to include not just about 0.1% to about 5%,but also the individual values (e.g., 1%, 2%, 3%, and 4%) and thesub-ranges (e.g., 0.1% to 0.5%, 1.1% to 2.2%, 3.3% to 4.4%) within theindicated range. The statement “about X to Y” has the same meaning as“about X to about Y,” unless indicated otherwise. Likewise, thestatement “about X, Y, or about Z” has the same meaning as “about X,about Y, or about Z,” unless indicated otherwise.

In this document, the terms “a,” “an,” or “the” are used to include oneor more than one unless the context clearly dictates otherwise. The term“or” is used to refer to a nonexclusive “or” unless otherwise indicated.The statement “at least one of A and B” has the same meaning as “A, B,or A and B.” In addition, it is to be understood that the phraseology orterminology employed herein, and not otherwise defined, is for thepurpose of description only and not of limitation. Any use of sectionheadings is intended to aid reading of the document and is not to beinterpreted as limiting; information that is relevant to a sectionheading may occur within or outside of that particular section.

In the methods described herein, the acts can be carried out in anyorder without departing from the principles of the invention, exceptwhen a temporal or operational sequence is explicitly recited.

Furthermore, specified acts can be carried out concurrently unlessexplicit claim language recites that they be carried out separately. Forexample, a claimed act of doing X and a claimed act of doing Y can beconducted simultaneously within a single operation, and the resultingprocess will fall within the literal scope of the claimed process.

The term “about” as used herein can allow for a degree of variability ina value or range, for example, within 10%, within 5%, or within 1% of astated value or of a stated limit of a range, and includes the exactstated value or range.

The term “substantially” as used herein refers to a majority of, ormostly, as in at least about 50%, 60%, 70%, 80%, 90%, 95%, 96%, 97%,98%, 99%, 99.5%, 99.9%, 99.99%, or at least about 99.999% or more, or100%.

The term “alkyl” as used herein refers to straight chain and branchedalkyl groups and cycloalkyl groups having from 1 to 40 carbon atoms, 1to about 20 carbon atoms, 1 to 12 carbons or, in some embodiments, from1 to 8 carbon atoms. Examples of straight chain alkyl groups includethose with from 1 to 8 carbon atoms such as methyl, ethyl, n-propyl,n-butyl, n-pentyl, n-hexyl, n-heptyl, and n-octyl groups. Examples ofbranched alkyl groups include, but are not limited to, isopropyl,iso-butyl, sec-butyl, t-butyl, neopentyl, isopentyl, and2,2-dimethylpropyl groups. As used herein, the term “alkyl” encompassesn-alkyl, isoalkyl, and anteisoalkyl groups as well as other branchedchain forms of alkyl. Representative substituted alkyl groups can besubstituted one or more times with any of the groups listed herein, forexample, amino, hydroxy, cyano, carboxy, nitro, thio, alkoxy, andhalogen groups.

The term amine as used herein refers to a substituent of the form —NH₂,—NHR, —NR₂, —NR₃ ⁺, wherein each R is independently selected, andprotonated forms of each, except for —NR₃ ⁺, which cannot be protonated.Accordingly, any compound substituted with an amino group can be viewedas an amine. An “amino group” within the meaning herein can be aprimary, secondary, tertiary, or quaternary amino group. An “alkylamino”group includes a monoalkylamino, dialkylamino, and trialkylamino group.

The term “hydrocarbon” or “hydrocarbyl” as used herein refers to amolecule or functional group that includes carbon and hydrogen atoms.The term can also refer to a molecule or functional group that normallyincludes both carbon and hydrogen atoms but wherein all the hydrogenatoms are substituted with other functional groups.

The term “room temperature” as used herein refers to a temperature ofabout 15° C. to 28° C.

Examples

Materials

TABLE 1 Materials Table. Designation Description EHA 2-Ethylhexylacrylate, available from BASF, Florham Park, NJ. IBOA Isobornylacrylate, available from San Esters, New York, NY. AA Acrylic acid,available from BASF, Florham Park, NJ. HEA 2-Hydroxyl ethyl acrylate,available from BASF, Florham Park, NJ. CN965 An aliphatic polyesterbased urethane diacrylate oligomer available under the trade designationCN965 from Sartomer Americas, Exton, PA. Irg 6512,2-Dimethoxy-1,2-diphenylethan-1-one, available under the tradedesignation IRGACURE 651 from BASF Corporation, Vandalia, IL. PVB1Poly(vinyl butyral), PVB, having a glass transition temperature (Tg) of70° C., available under the trade designation MOWITAL B60H from Kuraray,Houston, TX. PVB2 Poly(vinyl butyral), PVB, having a glass transitiontemperature (Tg) of 65° C., available under the trade designationMOWITAL B60HH from Kuraray, Houston, TX. LA410 Block copolymer ofpoly(methyl methacrylate) and poly(n-butyl acrylate), available underthe trade designation KURARITY 410L from Kuraray Co., Ltd, Houston, TX.LA4285 Block copolymer of poly(methyl methacrylate) and poly(n-butylacrylate), available under the trade designation KURARITY 4285 fromKuraray Co., Ltd, Houston, TX. EHOAc 2-ethyl hexyl acetate, availablefrom Eastman Chemical Company, Kingsport, TN. PET1 A silicone releaseliner having a nominal thickness of 51 micrometers (0.002 inches),obtained from DuPont Teijin, DuPont Chemical Company, Wilmington DE.PET2 A corona treated and chemically primed PET film having a nominalthickness of 76 micrometers (0.003 inches), obtained from 3M Company,St. Paul, MN. UNIPLEX Polypropylene glycol dibenzoate obtained fromRhein Chemie 145 Parker Court 400 Chardon, Ohio, 44024 United StatesH9010 HALLGREEN 9010, a renewable ester plasticizer available fromHallstar, 120 South Riverside Plaza, Suite 1620, Chicago, IL 60606United States

TABLE 2 Composition Formulations Formulation Information (grams) 50%CN965 Irg Copolymer Copolymer Plasticizer Plasticizer Example EHA HEA inIBOA AA 651 Type Loading Add Type Loading 1 39 6.5 19.5 5 0.2 PVB1 15EHOAc 15 2 30 5 15 5 0.2 PVB1 15 EHOAc 30 3 39 6.5 19.5 5 0.23 PVB1 15EHOAc 15 4 39 6.5 19.5 5 0.23 PVB1 15 EHOAc 15 5 34 6.5 19.5 10 0.23PVB1 15 EHOAc 15 6 32 7 21 10 0.23 LA410 15 EHOAc 15 7 30 5 15 5 0.23PVB1 15 EHOAc 30 8 42 7 21 0 0.23 LA410 15 EHOAc 15 9 37 7 21 5 0.23LA410 15 EHOAc 15 10 21 3.5 10.5 5 0.23 PVB1 15 EHOAc 45 11 42 7 21 00.23 LA410 15 EHOAc 15 12 42 7 21 0 0.23 LA410 15 EHOAc 15 13 33 5.516.5 0 0.23 LA410 15 EHOAc 30 14 24 4 12 0 0.23 LA410 15 EHOAc 45 15 213.5 10.5 5 0.23 PVB1 15 EHOAc 45 16 34.1 4.9 14.6 2.4 0.22 PVB1 14.6UNIPLEX 400 29 17 35 5 15 0 0.23 LA410 15 UNIPLEX 400 30 18 20 5 15 00.23 LA410 15 UNIPLEX 400 45 19 35 5 15 0 0.23 LA4285 15 UNIPLEX 400 3020 20 5 15 0 0.23 LA4285 15 UNIPLEX 400 45 21 35.75 2.75 8.25 0 0.23LA410 15 H9010 30 22 35.75 0 8.25 2.75 0.23 LA410 15 H9010 30 23 39 6.519.5 5 0.20 PVB2 15 EHOAc 15 24 37 7 21 5 0.23 PVB1 15 EHOAc 15 25 37 721 5 0.23 PVB2 15 EHOAc 15Preparation of the Compositions for UV-Curing

Compositions were prepared by mixing the components in the amounts shownin Table 2 as follows. For samples which contain PVB (PVB1 or PVB2), theacrylic monomers, crosslinker, plasticizer, PVB and photoinitiator werecombined in a MAX100 speedmix cup, and mixed using a centrifugal resinmixer (Max 100 mixing cup and FlackTek SPEEDMIXER DAC 150 FV; both fromFlackTek Incorporated, Landrum, S.C.) at 3000 rpm for 5 minutes toprovide a homogeneous mixture.

For samples which contained LA410 or LA4285, all the components werecombined in the mixing cup, and then the solution was allowed to rollovernight to dissolve the polymer in the acrylic monomers. For sampleswhich contain no copolymer add, the EHA polymer was prepared first bycharging a 0.95 liter (1 quart) jar with 400 grams of EHA and 0.16 gramsof Irg 651, and stirred until the photoinitiator had dissolved and ahomogeneous mixture was obtained. The mixture was degassed byintroducing nitrogen gas into it through a tube inserted through anopening in the jar's cap and bubbling vigorously for at least 5 minutes.While stirring, the mixture was exposed to UV-A light until apre-adhesive composition having a viscosity deemed suitable for coatingwas formed. Following UV exposure, air was introduced into the jar. Thelight source was an array of LEDs having a peak emission wavelength of365 nm. Then all components for the sample, including the EHA polymercomposition were combined in a Max100 cup and mixed using a centrifugalresin mixer at 3000 rpm for 2 minutes to provide a homogeneous solution.

Preparation of Adhesive Films

The compositions were coated between the PET1 release liner and the PET2film backing using a two-roll coater having a gap setting of 0.002inches (51 micrometers) greater than that combined thickness of the twoliners, and exposed to a total UV-A energy of approximately 1824millijoules/square centimeter using a plurality of fluorescent bulbshaving a peak emission wavelength of 350 nanometers. The total UV-Aenergy was determined using a POWER PUCK II radiometer equipped with lowpower sensing head (available from EIT Incorporated, Sterling, Va.) at aweb speed of 4.6 meters/minute (15 feet/minute). The radiometer webspeed and energy were then used to calculate the total exposure energyat the web speed using during curing of the composition. Unlessotherwise indicated, the PET1 release liner was subsequently removed toprovide a self-wetting adhesive tape for testing according to the testmethods described below.

Test Methods

180° Peel Adhesion Test

A test sample was prepared by placing a 0.5 (12.2 cm) inch wide by 7inch (178 cm) long self-wetting adhesive coated tape on a 100 cm by 250cm glass. The plates were cleaned by wiping with isopropanol beforetesting. The tape was rolled down onto the panel with two passes of a 2kg roller. The test was conducted on a slip/peel tester (InstrumentorsInc.; Strongsville, Ohio). The tape was removed from the plate at a peelangle of 180° and a platen speed of 12 inches per minute (305 mm/min)for a total of 5 seconds. The force required to remove the tape wasmeasured in grams per 0.5 inch and converted to grams per inch (g/in).All testing was carried out at CTH conditions of 23° C. and 50% relativehumidity (RH). Prior to testing, samples were conditioned for a 10minute dwell time on the glass substrate at CTH conditions. Results arethe average of three tests for each adhesive. The results are shown inTable 3, reported as both grams per inch (g/in) and Newtons perdecimeter (N/dm). In Table 3, NT means that the sample was not tested.

TABLE 3 180° Peel Adhesion Test Results 180 degree Peel 180 degree PeelGlass 10 min Glass 10 min Example (g/in) (N/dm) 1 94.970825 3.692913 220.695135 0.804724 3 NT NT 4 83.34753 3.240945 5 NT NT 6 NT NT 724.38057 0.948031 8 NT NT 9 NT NT 10 34.869885 1.355906 11 7.6543650.297638 12 7.37087 0.286614 13 0.283495 0.011024 14 0 0 15 34.8698851.355906 16 NT NT 17 NT NT 18 NT NT 19 NT NT 20 NT NTWet Out Test

A glass slide with dimensions of 7.62 cm (3 inch) by 2.54 cm (1 inch)was held at an angle of 69° and dropped on the self-wetting adhesivesurface. The time to wet out the glass slide was recorded in seconds anddivided by the area wet out (e.g., 3 in² for the glass slide). The testwas performed three times for each sample, and the average was reportedas shown in Table 4. Results are reported as both seconds per squareinch (s/in^(t)) and seconds per decimeter (s/dm²).

TABLE 4 Wet Out Test Results Wet Wet Out Example Out (s/dm²) (s/in²) 1142.6 9.2 2 35.6 2.3 3 240.2 15.5 4 127.1 8.2 5 598.3 38.6 6 155.0 10 725.6 2.3 8 31.0 2 9 58.9 3.8 10 26.3 1.7 11 34.1 2.2 12 24.8 1.6 13 10.80.7 14 4.6 0.3 15 26.3 1.7 16 49.6 3.2 17 38.7 2.5 18 43.4 2.8 19 51.13.3 20 65.1 4.290° Peel Adhesion on Linear Polarizer Test

A test sample was prepared by placing a 2.54 cm (1 inch) wide by 20.32cm (8 inch) long adhesive coated structured film on a linear polarizer,model LLC2-81-18 (SanRitz Co.; Tokyo, Japan). The adhesive coatedstructured film was prepared by overcoating one of the adhesiveformulations on to a structured film. The structured film includessinusoidal structures of an acrylate resin on the primed side of a 0.75mm (3 mil) thick PET film, MELINEX 454 (Teijin DuPont Films; Chester,Va.) made by a cast and cure process, as described in U.S. Pat. Nos.5,175,030 and 5,183,597. The sinusoidal structures have a peak-to-valleyheight of 1.4 micron and a pitch (peak-to-peak or valley-to-valleydistance) of 7.5 micron. The adhesive coated structured film was rolleddown onto the linear polarizer with two passes of a roller using lighthand pressure.

The test was conducted on an iMass SP-2100 Slip/Peel Tester (IMASS,Inc.; Accord, Mass.). The adhesive coated structured film was removedfrom the linear polarizer at a peel angle of 90° and a platen speed of76.2 cm/min (30 inches per minute) for a total of 5 seconds, after agingon the linear polarizer. Test sample aging was carried out for 0 hoursat 20° C., 72 hours at 20° C., and 72 hours at 85° C. The force requiredto remove the adhesive coated structured film was measured in pounds perinch (lb/in). Results are the average of two tests for each test sample.The results are shown in Table 5. Results are also reported as g/in andN/dm.

TABLE 5 90° Peel Adhesion on Linear Polarizer Test Results Aging Aging90 degree 90 degree 90 degree Temperature Time Peel Peel Peel Example(C.) (hours) (lb/in) (g/in) (N/dm) 21 20 0 0.0635 28.80 1.12 21 20 720.1035 46.95 1.83 21 85 72 0.1135 51.48 2.00 22 20 0 0.1493 67.72 2.6322 20 72 0.2108 95.62 3.72 22 85 72 0.5503 249.61 9.71Scratch Resistance Test

Scratch resistance tests were performed using a TABER Linear AbraserModel 5750 (Taber Industries; North Tonawanda, N.Y.) with apolypropylene stylus attachment. The instrument has a free-floatinghorizontal arm that moves back and forth in a linear motion, and avertical spline shaft is attached to the horizontal arm to allow weightto be added to the shaft. For each experiment, the samples were cut intoapproximately 3.81 cm (1.5 inch) by 2.54 cm (1 inch) strips. The PET1silicone release liner was peeled off and the adhesive/backing wasmounted onto glass slides with a roller. The test specimen was affixedto the bottom of the spline shaft so that the stylus attachment wastouching the backing. Tests were performed where the shaft was mountedwith a no weight disc, 1 weight disc, 2 weight discs, and 3 weightdiscs, corresponding to subjecting the specimen to 350 grams, 600 grams,850 grams, and 1100 grams of weight, respectively. Each specimen wassubjected to one linear stroke (half of a cycle) of scratching, at aspeed of either 0.16 cm/s or 1.3 cm/s of horizontal abraser armmovement. A fresh sample was used for each speed and weight combination.

Results of the scratch resistance tests are shown in FIGS. 1-3 .

FIG. 1 shows a photograph of scratch testing results with the TABERAbraser for Example 1, which includes PVB (PVB1). As shown in FIG. 1 ,sample 1 is able to withstand the scratch test. In this image, thesample have been removed from the glass substrate and turned over, sothe adhesive side is facing the camera.

FIG. 2 shows a photograph of scratch testing results with the TABERAbraser for Example 8. In this image, the sample have been removed fromthe glass substrate and turned over, so the adhesive side is facing thecamera. The stylus imparted permanent damage to Example 8, whichincluded no PVB, with clearly observable scratch marks and leavingresidue on the glass substrate.

FIG. 3 shows a photograph of scratch testing results with theTABERAbraser for Example 9. In this image, the sample have been removedfrom the glass substrate and turned over, so the adhesive side is facingthe camera. The stylus imparted permanent damage to Example 9, whichincluded no PVB, with clearly observable scratch marks and leavingresidue on the glass substrate.

Shear Test Method

Static shear was determined according to the method of ASTM D3654-82entitled, “Holding Power of Pressure-Sensitive Tapes,” with thefollowing modifications. The release liner(s), where present, wasremoved from the test sample. The conditions for CTH were 70° F. (21°C.) and 50% RH. For high humidity experiments the conditions were 90° F.(32° C.) and 90% RH. Samples of 1.27 cm (0.5 inch) wide by 7.62 cm (3inch) long adhesive coated tape were die-cut in replicates of three. Thefirst 1.27 cm (0.5 inch) of the adhesive in the length direction wasadhered to the edge of the glass substrates of 5.08 cm (2 inch) by 5.08cm (2 inch) by passing a 6.8 kg (15 lb) hand held roller over the lengthof the sample two times at a rate of 30.48 cm/min (12 in/min). The otherside of the adhesive was folded onto itself and stapled to provide ahook type shape in order to hang a hanger and then weight. Samples weremounted on Static Shear stands (CHEMInstruments; Fairfield, Ohio).

The test sample was allowed to dwell on the test substrate for 1 hour at21° C. and 50% RH for CTH testing and 90° F. (32° C.) and 90% RH forhigh humidity testing; thereafter a 2000 g, 3000 g, or 4000 g weight wasapplied to the hanger. The time to failure was recorded in minutes andthe average value, calculated pursuant to procedures A and C of section10.1 of the standard, for all of the test samples was reported. Foursamples were tested and the average time to failure of the four sampleswas recorded. Results are shown in Table 6.

TABLE 6 Shear test results. Shear Glass Shear Glass Shear Glass ShearGlass 6.6 lb/in² Shear Glass 8.8 lb/in² 4.4 lb/in² CTH 6.6 lb/in² CTH90° F./90% RH 8.8 lb/in² 90° F./90% RH Example (min) (min) (min) CTH(min) (min) 1 3 NT NT NT NT 2 44435 NT NT NT NT 3 34209 34209 NT NT NT 4NT 24480 24480 NT NT 5 10 24155 NT NT NT 6 NT 22811 NT NT NT 7 NT 1632010560 NT NT 8 44398 78 NT NT NT 9 5495 43.6 NT NT NT 10 0 0 0 NT NT 11 00 480 NT NT 12 0 NT 0 NT NT 13 0 0 0 NT NT 14 0 0 0 NT NT 15 NT 0 0 NTNT 16 44472 NT NT NT NT 17 44435 NT NT NT NT 18 10 NT NT NT NT 19 44398NT NT NT NT 20 5495 NT NT NT NTWeight Hanging Test

Self-wetting adhesive hook articles were prepared as follows. Theuncoated side of the PET2 film backing of a self-wetting adhesive coatedtape sample was primed using 3M Adhesion Promoter 4298UV, available from3M Company, St. Paul, Minn. Then an acrylic adhesive (2 mil thick 3M300LSE acrylic adhesive provided on a release liner, available from 3MCompany, St. Paul, Minn.), was adhered to the primed side of the PET2film backing. The release liner was removed from the 300LSE acrylicadhesive and a 15 mil thick clear polycarbonate film, which had beencorona treated and primed, was then adhered to the 300LSE acrylicadhesive. The test samples were square shaped and varied in size, asindicated in Table 7 (areas of 1.5, 2.5, 3.5, 4.5 in²). Each test samplewas then sent through a roll-to-roll laminator twice with the laminatorpressure set to approximately 25 psi and a line speed of approximately30 in/min. Finally, an injection molded polycarbonate hook with a basearea of about 0.25 in² to 1 in² (corresponding to the different sizedsamples) was adhered to the polycarbonate film using an acrylic adhesive(3M SCOTCH-WELD Metal Bonder Acrylic Adhesive DP8407NS, available from3M Company, St. Paul, Minn. The hook was centrally positioned on an edgeof the polycarbonate film and attached approximately 0.25 inch above thefilm edge, so that the weights used in the hanging weight test werehanging from the bottom of the hook article. The self-wetting adhesivehook article was then allowed to dwell at room temperature for at least72 hours.

The self-wetting adhesive hook article was then attached to the adherend(tile, stainless steel, glass, varnished wood, etc.) by hand undermoderate pressure (roughly 5 pounds) until complete wet out of theadhesive on the adherend was observed. After a one hour dwell time,brass weights (2, 4, 5, 6, 7 or 8 lb) were suspended from the hook.Samples were tested at ambient indoor conditions (approximately 21° C.and 50% RH) or in a shower spray chamber at 95%+ relative humidity witha continuous H₂O spray with a water temperature of 105° F.−120° F. (41°C.-49° C.). The test samples were observed once a day for three weeksand failures were recorded at each time point. Failure was indicatedwhen it was observed that hook article completely fell off the adherend(the self-wetting adhesive no longer adhered to the adherend surface).All samples were tested in 2 replicates. Each Time Under Loadperformance value reported in Table 7 is an average of the hang time forall the replicates of a given example such that the maximum performancevalue would be 21 days and the minimum performance value would be 0days. If the weighted samples had not failed at the 3 weeks deadline,the data was recorded as 21+ days.

TABLE 7 Weight Hanging Test Results Time Sample Brass Under Size weightLoad Example (in²) Adherend Environment (lb) (days) 25 1.5 Tile¹ Lab 521+ 23 1.5 Varnished Wood² Lab 3 21+ 25 1.5 Tile Shower 2 18 25 2.5 TileLab 7 21+ 24 2.5 Shower insert³ Lab 5 21+ 25 2.5 Varnished Wood Lab 521+ 25 2.5 Tile Shower 4 21+ 25 2.5 Glass⁴ Shower 4 21+ 25 2.5 Showerinsert Shower 4 21+ 25 3.5 Stainless Steel Shower 6 21+ 25 4.5 StainlessSteel Shower 8 21+ ¹White Glazed Ceramic Wall Tile (Interceramic,Carollton, TX) ²Glossy finish ³Fiberglass reinforced acrylic/ABS, smoothfinish ⁴Non-tin side

Additional Embodiments

The following exemplary embodiments are provided, the numbering of whichis not to be construed as designating levels of importance:

Embodiment 1 provides a composition comprising:

-   -   a) about 5 to about 40 parts by weight of a solute copolymer        component optionally having one T_(g) or T_(m) of at least 25°        C.;    -   b) about 60 to about 95 parts by weight of a solvent monomer        component comprising (meth)acrylate monomers and a        multifunctional acrylate, wherein the sum of a) and b) is 100        parts by weight; and    -   c) about 5 to about 100 parts of a plasticizer, relative to 100        parts a) and b).

Embodiment 2 provides the composition of claim 1, wherein the solventmonomer component comprises:

-   -   d) about 5 to about 95 parts by weight of low T_(g) monomers;    -   e) about 0 to about 20 parts of an acid functional monomer;    -   f) about 0 to about 20 parts of a non-acid functional polar        monomer; and    -   g) about 5 to about 40 parts of a multifunctional acrylate        cross-linking agent,    -   wherein the sum of d) to g) is 100 parts by weight.

Embodiment 3 provides the composition of any one of claim 1 or 2,wherein the composition is a syrup polymer composition.

Embodiment 4 provides the composition of claim 3, wherein the syruppolymer composition has a viscosity of from about 500 to about 10,000 cPat 22° C.

Embodiment 5 provides the composition of any one of claims 1-4, whereinthe solute copolymer is selected from a polyurethane, a polyester, apolyvinylpyrrolidone, a poly(methyl methacrylate), a poly(butylacrylate), a polymer derived from a polyvinyl alcohol and an alkanal, apolyacrylonitrile, a polyolefin, a polyurea, a polybutadiene, apolystyrene, any copolymer thereof, and any combination thereof.

Embodiment 6 provides the composition of claim 5, wherein the alkanalhas the structure:

-   -   wherein R¹ is selected from (C₁-C₂₀)hydrocarbyl.

Embodiment 7 provides the composition of claim 6, wherein R¹ is(C₁-C₂₀)alkyl.

Embodiment 8 provides the composition of any one of claims 5-7, whereinsolute copolymer component comprises a poly(vinyl butyral).

Embodiment 9 provides the composition of any one of claims 1-8, whereinthe solute copolymer comprises a block copolymer of poly(methylmethacrylate) and poly(n-butyl acrylate).

Embodiment 10 provides the composition of any one of claims 2-9, whereinthe solvent monomer comprises about 0 to 15 parts by weight ofacid-functional monomer and about 60 to about 90 parts by weight of thelow T_(g) monomer.

Embodiment 11 provides the composition of any one of claims 1-10,wherein the solvent monomer component comprises about 20 to about 60parts by weight of low T_(g) monomer units.

Embodiment 12 provides the composition of any one of claims 1-11,wherein at the solute copolymer is about 10 parts to about 20 parts byweight of the composition.

Embodiment 13 provides the composition of any one of claims 2-12,wherein at least one of the acid functional monomer in the solventmonomer is at least one of an ethylenically unsaturated carboxylic acid,an ethylenically unsaturated sulfonic acid, an ethylenically, andunsaturated phosphonic acid.

Embodiment 14 provides the composition of any one of claims 2-13,wherein the non-acid functional polar monomer in the solvent monomer isethylenically unsaturated hydroxyl containing monomer, an ethylenicallyunsaturated amine containing monomer, or a combination thereof.

Embodiment 15 provides the composition of any one of claims 2-14,wherein the solvent monomer component comprises about 0 to about 15parts by weight of the non-acid functional polar monomer.

Embodiment 16 provides the composition of any one of claims 2-15,wherein the solvent monomer component comprises about 0 to about 15parts by weight of the acid-functional monomer.

Embodiment 17 provides the composition of any one of claims 1-16,wherein the composition comprises about 10 to about 80 parts of theplasticizer, relative to 100 parts of a) and b).

Embodiment 18 provides the composition of any one of claims 1-17,wherein the plasticizer is at least one of aliphatic monoalkyl esters,aromatic monoalkyl esters, aliphatic polyalkyl esters, aromaticpolyalkyl esters, polyalkyl esters of aliphatic alcohols, phosphonicpolyalkyl esters, aliphatic poly(alkoxylated) esters, aromaticpoly(alkoxylated) esters, poly(alkoxylated) ethers of aliphaticalcohols, and poly(alkoxylated) ethers of phenols.

Embodiment 19 provides a film formed from the composition of any one ofclaims 1-18.

Embodiment 20 provides the film of claim 19, wherein the film is a curedadhesive film.

Embodiment 21 provides the cured adhesive film of any one of claim 19 or20, wherein the film is scratch resistant when subjected to a linearstroke of a stylus of having a speed of at least 0.16 cm/s and a weightapplied to the stylus ranges from about 0 grams to about 1500 grams.

Embodiment 22 provides the cured adhesive film of claim 21, wherein thefilm is more scratch resistant than a corresponding film that issubstantially free of the solute copolymer component.

Embodiment 23 provides the cured adhesive film of any one of claims20-22, wherein a 0.5 inch wide by 0.5 inch long sample of the filmremains adhered to a substrate for a time ranging from approximately 10minutes to 40 days when a force ranging from about 2 lbs/in.² to about10 lbs/in^(t) is applied to the film.

Embodiment 24 provides the cured adhesive film of claim 23, wherein thefilm remains adhered to the substrate for a time ranging up to about 30days.

Embodiment 25 provides the cured adhesive film of any one of claim 23 or24, wherein the film remains adhered to the substrate for a time rangingfrom about 5 days to about 10 days.

Embodiment 26 provides the cured adhesive film of any one of claims20-25, wherein the film remains adhered to the substrate for asubstantially longer period of time than a corresponding film that issubstantially free of the solute copolymer component.

Embodiment 27 provides the cured adhesive film of any one of claims20-26, wherein a wet-out rate of the film ranges from about 0.5 s/in² toabout 50 s/in².

Embodiment 28 provides the cured adhesive film of any one of claims20-27, wherein a wet-out rate of the film ranges from about 27 s/in² toabout 40 s/in².

Embodiment 29 provides the cured adhesive film of any one of claims20-28, wherein a wet-out rate of the film ranges from about 0.5 s/in² toabout 10 s/in².

Embodiment 30 provides the cured adhesive film of any one of claims20-29, wherein a force to peel the film from a glass substrate at a peelangle of 180 degrees and at a speed of 12 in/min ranges from about 0.1N/dm to about 10 N/dm.

Embodiment 31 provides the cured adhesive film of any one of claims20-30, wherein a force to peel the film from a glass substrate at a peelangle of 180 degrees and at a speed of 12 in/min ranges from about 0.1N/dm to about 5 N/dm.

Embodiment 32 provides the cured adhesive film of any one of claims20-30, wherein the cured adhesive film is applied to a polarizer.

Embodiment 33 provides an adhesive article comprising a layer of thecured adhesive film of any one of claims 20-30 disposed on an opticalfilm.

Embodiment 34 provides the adhesive article of claim 33 wherein theoptical film is a multilayer optical film.

Embodiment 35 provides the adhesive article of claim 33 wherein theoptical film is a microstructured optical film.

Embodiment 36 provides the adhesive article of claim 33 furthercomprising a release liner disposed on the surface of the cured adhesivefilm opposite the optical film.

Embodiment 37 provides a method of making a cured adhesive filmcomprising photopolymerizing the composition of any one of claims 1-31.

Embodiment 38 provides a method of making a cured adhesive filmcomprising:

-   -   forming a film of the composition of any one of claims 1-32; and    -   photopolymerizing the composition.

Embodiment 39 provides a method of making a cured adhesive filmcomprising:

-   -   at least partially polymerizing a composition comprising    -   a) about 60 to about 95 parts by weight of a solvent monomer        component comprising (meth)acrylate monomers and a        multifunctional acrylate; and    -   b) about 5 to about 40 parts by weight of a solute copolymer        component optionally having one T_(g) or T_(m) of at least 25°        C.;        -   wherein the sum of h) and i) is 100 parts by weight;    -   to give an at least partially polymerized composition.

Embodiment 40 provides the method of claim 39, further comprising:

-   -   c) adding about 5 to about 40 parts of a multifunctional        acrylate cross-linking agent; and    -   d) about 5 to about 100 parts of a plasticizer, relative to 100        parts a) and b) to the at least partially polymerized        composition to obtain a second composition; and    -   further photopolymerizing the second composition.

The invention claimed is:
 1. A composition comprising: a) about 5 toabout 40 parts by weight of a solute copolymer component optionallyhaving one T_(g) or T_(m) of at least 25° C.; b) about 60 to about 95parts by weight of a solvent monomer component comprising (meth)acrylatemonomers and a multifunctional acrylate, wherein the sum of a) and b) is100 parts by weight; and c) about 5 to about 100 parts of a plasticizer,relative to 100 parts a) and b).
 2. The composition of claim 1, whereinthe solvent monomer component comprises: d) about 5 to about 95 parts byweight of low T_(g) monomers; e) about 0 to about 20 parts of an acidfunctional monomer; f) about 0 to about 20 parts of a non-acidfunctional polar monomer; and g) about 5 to about 40 parts of amultifunctional acrylate cross-linking agent, wherein the sum of d) tog) is 100 parts by weight.
 3. The composition of claim 1, wherein thecomposition is a syrup polymer composition.
 4. The composition of claim3, wherein the syrup polymer composition has a viscosity of from about500 to about 10,000 cP at 22° C.
 5. The composition of claim 1, whereinthe solute copolymer is selected from a polyurethane, a polyester, apolyvinylpyrrolidone, a poly(methyl methacrylate), a poly(butylacrylate), a polymer derived from a polyvinyl alcohol and an alkanal, apolyacrylonitrile, a polyolefin, a polyurea, a polybutadiene, apolystyrene, any copolymer thereof, and any combination thereof.
 6. Thecomposition of claim 5, wherein solute copolymer component comprises apoly(vinyl butyral).
 7. The composition of claim 1, wherein the solutecopolymer comprises a block copolymer of poly(methyl methacrylate) andpoly(n-butyl acrylate).
 8. The composition of claim 2, wherein thesolvent monomer comprises about 0 to 15 parts by weight ofacid-functional monomer and about 60 to about 90 parts by weight of thelow T_(g) monomer.
 9. The composition of claim 1, wherein at the solutecopolymer is about 10 parts to about 20 parts by weight of thecomposition.
 10. The composition of claim 2, wherein at least one of theacid functional monomer in the solvent monomer is at least one of anethylenically unsaturated carboxylic acid, an ethylenically unsaturatedsulfonic acid, an ethylenically, and unsaturated phosphonic acid. 11.The composition of claim 2, wherein the non-acid functional polarmonomer in the solvent monomer is ethylenically unsaturated hydroxylcontaining monomer, an ethylenically unsaturated amine containingmonomer, or a combination thereof.
 12. The composition of claim 2,wherein the solvent monomer component comprises about 0 to about 15parts by weight of the non-acid functional polar monomer, and whereinthe solvent monomer component comprises about 0 to about 15 parts byweight of the acid-functional monomer.
 13. The composition of claim 1,wherein the composition comprises about 10 to about 80 parts of theplasticizer, relative to 100 parts of a) and b).
 14. A film formed fromthe composition of claim
 1. 15. The film of claim 14, wherein the filmis a cured adhesive film.
 16. The cured adhesive film of claim 15,wherein the film is scratch resistant when subjected to a linear strokeof a stylus of having a speed of at least 0.16 cm/s and a weight appliedto the stylus ranges from about 0 grams to about 1500 grams.
 17. Thecured adhesive film of claim 15, wherein a 0.5 inch wide by 0.5 inchlong sample of the film remains adhered to a substrate for a timeranging from approximately 10 minutes to 40 days when a force rangingfrom about 2 lbs/in.² to about 10 lbs/in² is applied to the film. 18.The cured adhesive film of claim 15, wherein the cured adhesive film isapplied to a polarizer.
 19. An adhesive article comprising a layer ofthe cured adhesive film of claim 15 disposed on an optical film.
 20. Theadhesive article of claim 19 wherein the optical film is at least one ofa multilayer optical film and a microstructured optical film.